Electrostatographic printers are known in which a toner image is electrostatically formed on photoreceptive image bearing member. The toner image is transferred to a receiving substrate, typically paper or other print receiving materials. The toner image is subsequently fused to the substrate.
In other electrostatographic printers a plurality of dry toner imaging systems, one image bearing member is used to develop multiple color toner images. Each color toner image is electrostatically transferred in layers from the image bearing members and registered to an intermediate transfer member. The composite toner image is electrostatically transferred to the final substrate. Such systems that use electrostatic transfer to transfer the composite toner image from the intermediate to the final substrate and then subsequently fix the image on the substrate in a fusing system have transfer limitations. For example, there are limitations due to stresses introduced with rougher paper stock, foils, paper moisture content variations, etc. Also, the need to electrostatically transfer a full layered color composite toner image to the substrate creates additional high stresses for electrostatic transfer.
Stressful system conditions can include for example systems that may wish to use papers allowed to condition at wide ranges of relative humidity, and systems that may wish to image onto a large range of paper roughness and widths. Such stresses can have significant effect on transfer due to the effect on the electrostatic fields used in electrostatic transfer, and they can also have significant effect on paper transport. In addition with direct to paper transfer, fibers, talc and other particulate or chemical contaminants can readily directly transfer from the paper to the imaging modules during direct contact in the electrostatic transfer zones. This can tend to contaminate the imaging drums, development systems, cleaner systems, etc., and can lead to early failure of the imaging systems. This is especially true for certain stressful paper types including for example certain types of recycled papers. Due to all these and other problems, systems that use direct transfer to the final media generally have narrow media latitude for obtaining and/or for maintaining high print quality.
Alternatively, a toner image is formed on a photoreceptor. The toner image is transferred to a transfuse member. The transfuse member is employed to generally simultaneously transfer and fuse the toner image to a substrate. The transfuse member preferably has good release properties for efficient transfer of the toner image to the substrate. However, materials having acceptable release properties can have unacceptably short component life therefore resulting in increased costs for replacement and increased printer down time. In addition, materials having acceptable release properties can fail to exhibit additional desirable transfer properties such as improved conformability for good transfer to rougher substrates.